[unreadable] In Phase I a novel low profile "no-fold" balloon suitable for angioplasty applications was successfully developed. In this grant application, the "no-fold" balloon technology will be applied to create a very low profile balloon catheter which will serve as a platform for an ultra low profile stent delivery catheter. An ultra low profile stent delivery catheter has broad clinical applicability in the field of interventional cardiology due to the current emphasis on stenting dilated coronary arteries. We will utilize this phase II grant to design, construct and characterize through physical, biocompatibility and animal testing, a fully functioning ultra low profile stent delivery balloon catheter device. After FDA approval the device will be ready for commercial production. The ultra low profile stent delivery balloon catheter device will incorporate the novel "no-fold" balloon developed in phase I. We will mount a commercially available stent, such as the Medtronic "Racer" cobalt-chromium stent in order to test our catheter device. It should be noted that any ballon expandable stent (including drug-eluting) is mountable on our catheter. We will demonstrate in Phase II that our ultra low profile stent delivery catheter will be an improved stent delivery and deployment platform due to its significantly lower overall crossing profile and decreased stiffness. Our goal is to achieve approximately a 33% reduction in the profile of our catheter when compared to current 3.0 mm stent delivery catheters (such as Medtronic S7 stent system). Clinical practitioners using our stent delivery catheter system will observe an increased ease in delivering a stent to a stenotic lesion and an increased ability to directly deploy the stent without requiring pre-dilation. Direct stenting has been shown in some clinical trials to improve clinical outcome. A successful project will be accomplished if all of the following goals can be realized. 1. Produce a stent delivery catheter incorporating the "no-fold" dilation element. 2. Construct a stent delivery catheter (3 mm), such that it exhibits a profile (including the stent) of about 0.030 in ( max 0.032 inch). 3. Demonstrate through physical testing that the burst strength, expansion curve, balloon shape and other physical properties of the device are suitable for a stent delivery catheter. 4. Show with biocompatibility studies that the device is non- toxic. 5. Demonstrate, with animal studies, that the safety, maneuverability and performance of the new device is equal to or better than a control selected from a currently available stent delivery catheter. [unreadable] [unreadable]